Combined viscosity pump and electric motor

ABSTRACT

A viscosity pump comprises an electrical stator, an electrical rotor, end plates, said electrical rotor being housed within said stator and within said end plates, a radial gap defined by said rotor and said stator and said end plates, said rotor or said stator and said end plates being rotatably drivable with respect to one another when electrical energy is supplied to said stator or said rotor, at least one pair of ports comprising an inlet port for the supply of fluid to be pumped in communication with said gap at one part thereof and an outlet port for fluid in communication with said gap at another part thereof and barrier means corresponding in number to the number of pairs of ports between said pair of inlet and outlet ports.

[ Feb. 26, 1974 1 COMBINED VISCOSITY PUMP AND ELECTRIC MOTOR [76] lnventor: William Alan Bullough, Croosways,

Hood Green, near Barnsley, England v [22] Filed: Mar. 31, 1972 [21] Appl. No.: 239,928

I Foreign Application Priority Data Apr. 3, 1971 Great Britain 8594/71 [52] U.S. Cl 417/356, 310/60, 415/90 [51] Int. Cl. F04b 17/00, F04b /04, F0ld 1/36 [58] Field of Search. 415/90; 417/356, 423; 310/58,

[56} References Cited UNlTED STATES PATENTS 1,069,408 8/1913 Gaede 415/ 1,975,965 10/1934 Meyer 415/90 2,777,394 1/1957 Modrovsky 415/90 2,898,032 8/1959 Katzenberger 417/356 X 3,037,457 6/1962 Sternlicht 415/90 3,348,490 10/1967 Katz 417/356 1/1972 Wagner 415/90 FOREIGN PATENTS OR APPLICATIONS 402,961 3/1943 Italy 415/90 891,039 3/1962 Great Britain 417/356 Primary Examiner-Carlton R. Croyle Assistant Examiner-Richard Sher Attorney, Agent, or Firm-L0we, King & Price [57] ABSTRACT A viscosity pump comprises an electrical stator, an electrical rotor, end plates, said electrical rotor being housed within said stator and within said end plates, a radial gap defined by said rotor and said stator and said end plates, said rotor or said stator and said end plates being rotatably drivable with respect to one another when electrical energy is supplied to said stator or said rotor, at least one pair of ports comprising an inlet port for the supply of fluid to be pumped in communication with said gap at one part thereof and an outlet port for fluid in communication with said gap at another part thereof and barrier means corresponding in number to the number of pairs of ports between said pair of inlet and outlet ports.

9 Claims, 22 Drawing Figures PATENIED FEB 2 6 I974 SHEET 1 OF 3 PATENTEBFEBZGIQH I $794,447

sum 3 UP 3 FIG.16.

This invention relates to fluid pumps of the type hereinafter referred to as viscosity pumps, but also known as drag pumps or fluid friction pumps. Such pumps have been known for many years, see for instance British Pat. Nos. 891 039, 700 833, 27457/1909, 13665/1900 and 4733/1879. In principle, a channel of any shape (and change of shape along its length) whose boundaries possess a nett (not zero) absolute velocity relative to earth will induce a flow in the direction of that velocity. The fluid will be moved from section to section against a range of pressure gradients and at a rate according to the size and geometry of the channel, the magnitude of the velocity and the fluid properties i.e., by virtue of the drag imposed on the fluid by the moving surfaces. The mode of the flow may be laminar or turbulent.

Such pumps consist essentially of a pump body with a circular aperture in which is located a rotor with a radial gap between the external periphery of the rotor and the internal periphery of the pump body, an inlet port communicating with the gap at one point, and an outlet or delivery port communicating with the gap at another point, with a wiper member in contact with the external periphery of the rotor to assist in wiping pump fluid from the periphery of the rotor, and diverting the fluid from the gap into the outlet port, the fluid being dragged along the gap from the inlet port to the'delivery port. Alternatively, in place of a wiper any decrease in gap dimension achieves the same result. In the past it has been the practice to drive the rotor from an external source e.g., by an electric motor via a shaft running through seals and bearings.

The object of the present invention is to eliminate the previous two part arrangement of such pumps i.e., a pump proper being one part and a pump mover being the other part which besides providing a more compact pump enables substantial savings in cost to be attained and allows glandless construction, if required, thus affording a quieter and more efficient unit.

is held stationary so that when electrical energy is supplied to the rotor the stator rotates, so that the stator and rotor have reversed roles. For either arrangement the field windings could be on the stator or on the rotor.

The barrier means and ports are carried on any stationary part of the pump/motor, and the function of the barrier means is to prevent short circuiting of the pumped fluid between the ports.

The barrier means could be a wiper. This could be a separately provided member or it could be integral with -a stationary part of the pump motor.

Alternatively, the barrier means could be a diminution of the gap between a pair of ports associated with that barrier means. Conveniently, this may be achieved by employing an eccentric rotor which gives an increased volume but at lower pressure for a pump/motor of similar dimensions, speed and fluid.

The eccentric rotor may alternatively, be rotatable within a stator having a recess or pocket in its internal periphery to accommodate a segment of the outer periphery of the rotor. Again a non-eccentric rotor may berotatable within a stator having a recess or pocket in its internal periphery. All these arrangements are aimed at diminishing the gap at the outlet port and so avoid the need for a wiper.

Any pump/motor could be provided with a plurality of barrier means and a corresponding number of pairs of inlet and outlet ports.

For glandless constructions of pump/motors the end plates may carry a stationary shaft on which the rotor is rotatably supported. Alternatively, the rotor may be According to the present invention a viscosity pump S comprises an electrical stator, an electrical rotor housed within the stator and within end plates, with a radial gap defined by the rotor and the stator'and the end plates, the rotor or stator and end plates being rotatably drivable with respect to one another when electrical energy is supplied to the stator or rotor, an inlet port for the supply of fluid to be pumped in communication with the gap at one part thereof and an outlet port for fluid in communication with the gap at another part thereof with barrier means between the inlet and outlet ports.

The invention thus recognises that what may be termed the stator of a pump viz., the pump body, may be combined with the stator of an electric motor while what may be termed the rotor of a pump may be combined with the rotor of an electric motor. Thus, one combination constitutes the rotor of both a motor and a pump and another combination constitutes a stator of both a motor and pump, so that the invention provides a pump/motor.

The usual arrangement will be to hold the stator stationary so that when electrical energy is supplied thereto the rotor rotates, but the invention does not preclude the converse arrangement whereby the rotor made fast with a rotatable shaft, the ends of which are secured in the side plates, preferably in recesses in the side plates in which recesses bearings are preferably located. As a further alternative, by providing the pump- /motor with three or more pairs of inlet and outlet ports the rotor becomes self-aligning hydrodynamically and runs self-balanced and self-lubricated. Preferably, for electrical symmetry, four pairs are provided or as many poles as there are pairs of ports.

The stator is conveniently of the laminated type and a rotor of the squirrel cage induction type of motor has been found satisfactory. Whilst the squirrel cage form of rotor and induction motor are eminently suitable for the proposed application, any form of rotor and type of motor may be used with a greater or lesser degree of success. However, the best shape of the motor/pump should be decided upon by different considerations than those influencing electric motor shape. Thus the best shape may be of greater axial length or greater diameter than existing conventional electric motors. For instance windage loss in the radial gap is no longer a loss but becomes the driving force of the pump, between a rotary and stationary part of the pump. lf idling, tha axial gap is kept small.

Considering, however, a conventional squirrel cage motor, the only modification that need be effected is the provision of end plates and barrier means both of which are preferably of non-magnetic and non conducting material. This type of material is also the most suitable for filling in any undesirable gaps in conventional motors i.e., when converting to pump duty.

The pump is reversible i.e., direction of rotation determines direction of flow.

The method according to the invention of inducing flow also helpscool the pump/motors i.e., by circulating fluid through the radial gap. Furthermore, the possibility arises of running the whole pump/motor submerged in a fluid of suitable characteristics i.e., with stator and/or rotor windings suitably insulated.

The pump/motor of the invention may have a connection to the machine exterior. Inthis way an external load may also be driven and the arrangement may also be reversed e.g., an external shaft connected to a rotor may drive a machine. With a stationary external shaft fast to a rotor, the rotatable stator may, say, have fan blades fastened to it. In both of these cases a dynamic seal would be necessary where the external shaft passed through the stator. In the submerged mode this seal would normally be dispensed with. An element of differential motion, with both the rotor and stator rotatable may be designed into this arrangement.

Furthermore, when employing a rotor rotatable about a stationary shaft with a gap between the internal periphery of the rotor and the shaft, a series pumpingaction may be attained by using this secondary gap as a secondary pump. This would require a port connection through the shaft to one side of the barrier means (held by the shaft) and a port on the other side of the barrier means would pass through the end plates to the (primary) gap. The relative position of the barrier means may be fixed so as to reduce out of balance forces.

The rotor and/or stator surfaces may be covered or filled (canned or potted) in order to help tribological performance; prevent chemical attack; to facilitate good electrical design in conjunction with good hydraulic design; to prevent leakage through the laminations. Furthermore, if variable speed electric motor constituents are used then a whole variety of pump characteristics could be achieved.

7 Under normal conditions the combined pump/motor will pump almost any kind of fluid (continum) and given adequate winding insulation will run submerged,

as previously mentioned. In addition to the diminution of the primary gap to provide a barrier means the primary gap may possess a variety of shapes depending on the requirements of pressure-flow characteristic, lubrication and avoidance of whirl, self-alignement and selfbalancing, cooling and electromagnetic considerations. The shape, however, should not be such as to allow too severe a local pressure drop which would cause undesirable cavitation.

The rotor and/or stator surfaces may be smooth or have a regular pattern generated on their surfaces to improve the pump performance.

The ports may be axial or radial. Radial ports may be full width, or drilled centrally, or staggered.

A gathering/distributing slot may lie between the port and (primary) gap. This will tend to enhance the hy draulic performance by improving flow development.

The wiper may be axially straight or skewed. It may be made from metal or plastics elastic material and be forced onto the surface to be wiped by having an interference fit, or by having a slide fit wiper operated upon by a spring or by pressure compensation from the outlet port. The wiper may be made of flexible shape and material or barrier means may stand clear of the moving surface. An element of self-regulation is thus built in and the possibility of blockage by contaminants is reing drawings in which:

FIG. 1 is a transverse sectional view through a first embodiment of pump/motor according to the invention;

FIG. 2 is a longitudinal section of the pump/motor of FIG. 1;

FIG. 3 is a view corresponding to FIG. 2 of a second embodiment of pump/motor; I

FIG. 4 is a view correspondingto FIG. 1 of a third embodiment of pump/motor;

FIG. 5 is a view corresponding to FIG. I of a fourth embodiment of pump/motor;

FIG. 6 is a longitudinal section of the pump/motor of FIG. 5; v I

FIG. 7 is a view corresponding to FIG. 2 of a further embodiment of pump/motor;

FIG. 8 is a view corresponding to FIG. I of a further embodiment of pump/motor;

FIG. 9 is a view corresponding to FIG. 1 of a further embodiment of pump/motor;

FIG. 10 is a view corresponding to FIG. 1 of a further.

embodiment of pump/motor;

FIG. 11 is a view of one arrangement of radial ports;

FIG. 12 is a view of another arrangement of radial ports; 7

FIG. 13 is a view of another arrangement of radial ports;

FIG. 14 is a view .of one arrangement of axial ports;

FIG. 15 is a view corresponding to FIG. 1 of a further embodiment of pump/motor;

FIG. 16 shows a skewed wiperarrangement;

FIG. 17 is a view corresponding to FIG. 1 ofa further embodiment of pump/motor;

FIG. 18 is a view corresponding to FIG. 1 of a further embodiment of pump/motor;

FIG. 19 is a view corresponding to FIG. 1 of a further embodiment of pump/motor;

FIG. 20 is a view corresponding to FIG. 1 of a further embodiment of pump/motor;

FIG. 21 is a view corresponding to FIG. 1 of a further embodiment of pump/motor; and,

FIG. 22 is a view corresponding to FIG. 1 of a further embodiment of pump/motor. I

The pump/motor of FIGS. 1 and 2 comprises a rotor l and a laminated stator 2 provided with windings 3. The rotor 1 has an external periphery 4 while the stator 2 has an internal periphery 5 between which peripheries is a radial gap 6. An inlet port 7 for fluid to be pumped is in communication with the gap 6 at one part thereof, while an outlet port 8 is in communication with the gap 6 at another part thereof, the two parts being separated by a barrier means 9 constituted by a straight and axially extending wiper in contact with the rotor periphery 4. The ends of the pump motor are closed by end plates 10 each having an internal face 11 and an external face 12. The end plates carry a stationary shaft 13 provided with. static seals 26 at their external face 12 while the rotor 1 is rotatably supported on bearings 14 on the shaft 13.

The electric motor exemplified in FIGS. 1 and 2 is of the shaded pole type, but of course basically any electric motor will suffice. In operation, with a supply of fluid to be-pumped available at the inlet port 7, supply of electrical energy to the stator 2, with the latter held stationary, rotates the rotor and fluid is dragged around the gap 6 from the inlet port 7 to the outlet port 8 where it is diverted from the gap 6 by the barrier means 9.

In the embodiment of FIG. 3 like parts are given like reference numerals, and the bearings 14 for the rotor are carried in recesses in th end plateslO. The shaft 13 i in the fluid to be pumped.

In the embodiment of FIG. 4, three pairs of inlet and outlet ports 7, 8-are shown which ensures that the rotor l is self-aligning hydrodynamically, and runs selfbalanced and self-lubricated. The stator 2 is provided at its internal periphery 5 with three pockets or recesses so that the three gaps 6 decrease in dimension towards the outlet ports 8.

The embodiment of FIGS. 5 and 6 shows the converse arrangement to the embodiments previously described in that the rotor 1 and stator 2 reverse their roles because the rotor 1 is held stationary by means of a shaft 16 connected thereto, so that when electrical energy is supplied to the stator 2 (depending upon whether the field windings are on the stator or the rotor), the stator 2 rotates. Thus the stator 2 could for instance carry fan blades shown diagrammatically at 17. In this converse arrangement the barrier means 9 is carried by the rotor and is in the contact with the stator periphery 5. Because the shaft 16 extends through an end plate 10 and because there is relative rotation between them, a dynamic seal 18 is provided,

while inlet and outlet-ports 7 and 8 pass through the rotor and extend into the shaft 16.

In the embodiment of FIG. 7 is shown the invention applied to the known helically grooved pump so that the gap 6 becomes helical. Although the stator 2 is shown helically grooved, the grooves could equally well be applied to the rotor l. The shaft(s) 13 could be of the stationary type (FIG. 1) or the rotatable type (FIG. 3). Again with one or more extensions to the shaft(s) 13 an external load could be driven. In this embodiment, the inlet port 7 is provided in one end plate 10, while the outlet port 8 is provided in the other end plate 10. No wiper or gap diminution is required because of the axial distance between the inlet and the outlet ports.

In the embodiment of FIG. 8 the rotor l'is eccentric, its outer periphery 4 is in contact with a separate barrier means 9 while the inner periphery 5 of the stator 2 is circular.

In the embodiment of FIG. 9, the rotor 1 is eccentric and a segment of its outer periphery 4 is located in the recess or pocket 15, a portion of the stator 2 constituting the barrier means 9.

The embodiment of FIG. 10 corresponds closely to that of FIG. 9 but the internal periphery 5 of the stator 2 is circular, and again a portion of the stator 2 constitutes the barrier means 9.

FIGS. 11 to 13 show three possible radial arrangements for pairs of inlet and outlet ports 7, 8. The pairs of ports are full width in FIG. 11, central in FIG. 12, or staggered in FIG. 13. The arrangement of FIG. 14 shows axial ports.

In the embodiment of FIG. 15, the internal periphery 5 of the stator 2 is provided at the inlet port 7 with a distributing slot 19, and at the outlet port 8 with a gathering slot 20 both slots tending to enhance the hydraulic performance by improving flow development.

FIG. 16 shows an embodiment employing a barrier means 9 in the form of a skewed wiper in contrast to an axial wiper of FIGS. 1, 2, 5 and 6.

As shown by FIG. 17, the barrier means 9 may be urged into contact with the external periphery 4 of the rotor by a spring 21. Again a spring could be used for the barrier means 9 of FIGS. 5 and 6.

As shown by FIG. 18, the barrier means 9 may be urged into contact with the external periphery 4 of the rotor hydraulically by a bleed line 22 from the outlet port 8. Alternatively the bleed line 22 could extend from another source of pressure.

As shown by FIG. 19, the barrier means 9 may be of flexible material.

As shown by FIG. 20, the barrier means 9 may stand clear of the external periphery 4 of the rotor.

As shown by FIG. 21, the barrier means 9 could be revolvable e.g., a cylinder. I

As shown by FIG. 22, the barrier means 9 could have a hydrodynamic tilt.

Of course, any of the arrangements of barrier means of FIGS. 17 to 22 could conversely be carried by the rotor 1 to abut the internal periphery 5 of the stator 2 in the converse situation where the roles of rotor and stator are reversed.

As shown by FIG. 2, between the inner face 11 of the end plates 10 and the rotor 1 there exist side channels 23, which may remain idle or may add to the generating capacity of the pump/motor in which latter case it is necessary for the barrier means to extend to the side channels 23.

The stationary shaft arrangement (FIG. 2) may also be employed to obtain aseries pumping action, by making use of a secondary gap 24 between the stationary shaft 13 and the rotor internal periphery 25. In practice low pressure fluid would be fed from the outlet port 8 01 the (primary) gap 6 to an inlet port of the secondary gap 24.

What I claim is:

1. A viscosity pump comprising an electrical stator, an electrical rotor, end plates, said electrical rotor being housed within said stator and within said end plates, a radial gap defined by said rotor and said stator and said end plates, means for mounting said rotor and said stator for relative rotation and being rotatably drivable with respect to one another when electrical energy is supplied to one, at least one pair of ports comprising an inlet port for the supply of fluid to be pumped in communication with said gap at one part thereof and an outlet port for fluid in communication with said gap at another part thereof and barrier means corresponding in number to the number of pairs of ports between said pair of inlet and outlet ports whereby the fluid is viscosity pumped in the radial gap from the inlet port to the outlet port.

2. A viscosity pump as claimed in claim 1, wherein said mounting means is such that the stator is held stationary so that upon the supply ofelectrical energy said rotor rotates.

3. A viscosity. pump as claimed in claim 1, wherein said mounting means is such that the rotor is held stationary so that upon the supply of electrical energy said stator rotates.

4. A viscosity pump as claimed in claim ll, wherein said barrier means and ports are carried on the stationary part of said pump.

5. A viscosity pump as claimed in claim 1, wherein said barrier means is a wiper extending down into the the rotor has a driving connection to the exterior. 

1. A viscosity pump comprising an electrical stator, an electrical rotor, end plates, said electrical rotor being housed within said stator and within said end plates, a radial gap defined by said rotor and said stator and said end plates, means for mounting said rotor and said stator for relative rotation and being rotatably drivable with respect to one another when electrical energy is supplied to one, at least one pair of ports comprising an inlet port for the supply of fluid to be pumped in communication with said gap at one part thereof and an outlet port for fluid in communication with said gap at another part thereof and barrier means corresponding in number to the number of pairs of ports between said pair of inlet and outlet ports whereby the fluid is viscosity pumped in the radial gap from the inlet port to the outlet port.
 2. A viscosity pump as claimed in claim 1, wherein said mounting means is such that the stator is held stationary so that upon the supply of electrical energy said rotor rotates.
 3. A viscosity pump as claimed in claim 1, wherein said mounting means is such that the rotor is held stationary so that upon the supply of electrical energy said stator rotates.
 4. A viscosity pump as claimed in claim 1, wherein said barrier means and ports are carried on the stationary part of said pump.
 5. A viscosity pump as claimed in claim 1, wherein said barrier means is a wiper extending down into the gap.
 6. A viscosity pump as claimed in claim 1, wherein said barrier means is a diminution of the gap between a pair of ports associated with that barrier means.
 7. A viscosity pump as claimed in claim 1, wherein said end plates carry a stationary shaft on which the rotor is rotatably supported.
 8. A viscosity pump as claimed in claim 1, wherein said rotor is made fast with a rotatable shaft the ends of which are secured in said side plates.
 9. A viscosity pump as claimed in claim 1, wherein the rotor has a driving connection to the exterior. 